Sexual vs asexual reproduction (Edexcel GCSE Biology): Revision Notes

Comparing Methods of Reproduction: Advantages & Disadvantages

Asexual Reproduction

Advantages:

• Quick Reproduction: Offspring are produced quickly due to the fast reproductive system, allowing organisms to colonise a new area rapidly.
• Only One Parent Needed: Organisms can reproduce whenever conditions are favourable without needing to wait for a mate.
  • Example: Aphids reproduce quickly in summer when food is plentiful.

Disadvantages:

• No Genetic Variation: Offspring are genetically identical to the parent, which can lead to an increased risk of passing on diseases.
• Limited Ability to Adapt: If the environment changes or conditions become unfavourable, the entire population can be affected due to the lack of genetic diversity.
  • Example: Black Sigatoka is a disease affecting banana plants. If there is an outbreak, all bananas are likely to be affected as they are not resistant.

Sexual Reproduction

Advantages:

• Genetic Variation: Sexual reproduction leads to diversity and genetic mixing, giving individuals different characteristics. This helps prevent the direct inheritance of diseases from parents.
• Adaptability: Organisms are better adapted to environmental changes, which can lead to natural selection and evolution, making species more resilient.

Disadvantages:

• Longer Process and More Energy Required: Organisms produce fewer offspring and need to expend energy to attract mates.
  • Example: Male bowerbirds build structures from twigs and perform dances to impress females.
• Two Parents Needed: In some species, this can be a problem, especially if individuals are isolated.
  • Example: Polar bears often live alone, and males may need to walk long distances (up to 100 miles) to find a mate.

(Genetic diversity offspring)

Natural Sexual example:

RUNNERS (strawberry plants)

Artificial Sexual Examples:

Underground storage. Tubers/Bulbs produce roots/shoots

(Genetically identical offspring)

Natural Asexual reproduction example:

Budding → In yeast where parent cell produces bud

Artificial Asexual reproduction example

• CUTTINGS